1 1 4 Neurological Technique 



commissura posterior alba and commissura anterior alba. Of 

 what is the com. ant. alba (ventral white commissure) com- 

 posed ? What is the relation of the columna posterior to the 

 radix posterior ? Columnae anterior and lateralis to radix 

 anterior ? 



3. Substantia alba (white matter). — Funiculi posteriores, com- 

 posed of the funiculus gracilis (Goll's column) and the funiculus 

 cuneatus (Burdach's column). Funiculi anteriores (direct pyra- 

 midal tract, etc.). Funiculi laterales (crossed pyramidal tract, 

 direct cerebellar tract, etc.). Radix anterior and radix posterior. 

 Attach the names to all structures represented in the drawing. 



{c) Comparison : Make careful drawings, exclusive of the 

 meninges, of sections taken in a similar way ( i ) at the level of 

 the seventh N. thoracalis, (2) at the level of the fifth N. lumbalis, 

 and (3) through the conus meduUaris. In the pars thoracalis, 

 on the mesial side of the cervix columnae posterioris, note the 

 nucleus dorsalis (Clark's column). Make the drawings to the 

 scale of the first one. Attach the names to such structures as 

 are not found in the first section or are greatly modified. 



When complete, lay the four drawings in series and by care- 

 ful comparison verify the following statements : 



1. In the conus medullaris (sacrococcygeal region) the sub- 

 stantia grisea is surrounded by a comparatively thin mantle of 

 substantia alba. The columnae posteriores are nearly as thick 

 as the columnae anteriores, and the commissura grisea is rela- 

 tively thicker than in any of the other sections. Is there a 

 columna lateralis ? Why should the substantia grisea here be 

 more abundant in proportion to substantia alba than at other 

 levels ? 



2. In the pars lumbalis the substantia alba begins to pre- 

 dominate. Why ? The columnae posteriores are still relatively 

 thick as compared with those of the more cephalad sections. 

 Are there columnae laterales in this region ? Compare the funi- 

 culi posteriores with those of the other sections. 



3. The pars thoracalis is characterized by its relatively small 

 amount of substantia grisea. The columnae posteriores and 



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